Re: Finished my F5 --- tms0425
tms0425, I'm getting closer to an F5 build and I'm curious as to how you attached the wiring to CVillers boards. Wire gauge used.
I've yet to find a way to setup two F5s in balanced mode, and I'm hoping the Conrad MF35-151.5's will handle the heat.
The remaining parts from Digikey arrive Thursday, so maybe by this weekend I'll hear
what everyone has been talking about.
tms0425 said:
tms0425, I'm getting closer to an F5 build and I'm curious as to how you attached the wiring to CVillers boards. Wire gauge used.
I've yet to find a way to setup two F5s in balanced mode, and I'm hoping the Conrad MF35-151.5's will handle the heat.
The remaining parts from Digikey arrive Thursday, so maybe by this weekend I'll hear
what everyone has been talking about.Attachments
Nice looking box there ichiban.
Tonight I made more progress... but first a step back. I took and then labelled a pic of what I did with the output resistors. Seems that its part of my penance to show it all but maybe it might save some other poor soul. Morgan Jones talks in his book about never working when you're tired or late at night... well its then or never around these here parts! The boards are messy, bits having been soldered in and out a good few times so excuse the looks ok?! So look, if it saves anyone else...
and here she is powered up in the workshop, front face on, lid in place. I ended up painting it a nice shade of metallic green. I have it inside now playing a disc but am about to head downstairs and have a listen before bedtime. thanks again to Nelson, Peter and all who helped out here. everyone.
Fran
Tonight I made more progress... but first a step back. I took and then labelled a pic of what I did with the output resistors. Seems that its part of my penance to show it all but maybe it might save some other poor soul. Morgan Jones talks in his book about never working when you're tired or late at night... well its then or never around these here parts! The boards are messy, bits having been soldered in and out a good few times so excuse the looks ok?! So look, if it saves anyone else...
An externally hosted image should be here but it was not working when we last tested it.
and here she is powered up in the workshop, front face on, lid in place. I ended up painting it a nice shade of metallic green. I have it inside now playing a disc but am about to head downstairs and have a listen before bedtime. thanks again to Nelson, Peter and all who helped out here. everyone.
An externally hosted image should be here but it was not working when we last tested it.
Fran
Re: Re: Finished my F5 --- tms0425
I wish I had some of those nice milled and drilled Conrads. Very nice
I'm not really sure you'll have enough dissapation to put 4 channels of those 2 sinks. If I recall it's 62w each, so might be tough with 4. Also, that layout of toroids will get one of them VERY close to the signal wires on the back panel. If you want to try it I would mock it up with the supply on the bench, handwired to 2 boards first, then try a 4 if all goes well. Instead of tapping the heatsinks for all of them right away, I would be inclined to use flat bar stock temporarily clamped over the pairs of Mosfets. If it won't work that way in free air, the closed case with toroids inside definitely wouldn't make it. With all that said, my pair does not run as hot as I though it would. The F4's run about 45 C biased up a little harder than Nelson recommended.
I used 16 gauge for V+/V-, power grounds, AC wiring, doubled 20g Cardas for the speaker outputs, and 1x22g Cardas for the signal input/grounds. You could go bigger as the holes are very oversized.ichiban said:
tms0425, I'm getting closer to an F5 build and I'm curious as to how you attached the wiring to CVillers boards. Wire gauge used.
I've yet to find a way to setup two F5s in balanced mode, and I'm hoping the Conrad MF35-151.5's will handle the heat.
The remaining parts from Digikey arrive Thursday, so maybe by this weekend I'll hear
I wish I had some of those nice milled and drilled Conrads. Very nice
I'm not really sure you'll have enough dissapation to put 4 channels of those 2 sinks. If I recall it's 62w each, so might be tough with 4. Also, that layout of toroids will get one of them VERY close to the signal wires on the back panel. If you want to try it I would mock it up with the supply on the bench, handwired to 2 boards first, then try a 4 if all goes well. Instead of tapping the heatsinks for all of them right away, I would be inclined to use flat bar stock temporarily clamped over the pairs of Mosfets. If it won't work that way in free air, the closed case with toroids inside definitely wouldn't make it. With all that said, my pair does not run as hot as I though it would. The F4's run about 45 C biased up a little harder than Nelson recommended.
Re: Re: Re: Re: Finished my F5 --- tms0425
Thanks, but all it is so far is a left over sheet of aluminum that is 12 inches wide and when the excess length is trimmed off will fit the back perfectly Your amp looks verrry nice. A wood front from a very old oak table leaf extension is what I'm considering, offset from the sinks.
That's exactly what I was considering, clamping first. Thank you for the reply.
Sounds like a plan, oh great one
Ah, em, cough, cough. Hoping for a balanced F5 in the F6-7-8 !¿ Big Grin
woodturner-fran said:
Thanks, but all it is so far is a left over sheet of aluminum that is 12 inches wide and when the excess length is trimmed off will fit the back perfectly
Your amp looks verrry nice. A wood front from a very old oak table leaf extension is what I'm considering, offset from the sinks.Thanks for the reply. Yeah, the Conrads are nice. Should have ordered four from cwujek's group buy. He's considering another.tms0425 said:
I wish I had some of those nice milled and drilled Conrads. Very nice
Instead of tapping the heatsinks for all of them right away, I would be inclined to use flat bar stock temporarily clamped over the pairs of Mosfets. If it won't work that way in free air, the closed case with toroids inside definitely wouldn't make it.
That's exactly what I was considering, clamping first. Thank you for the reply.
Nelson Pass said:
Just adjust the bias until the sinks run 50-55 deg C, and there you are.
Sounds like a plan, oh great one
Ah, em, cough, cough. Hoping for a balanced F5 in the F6-7-8 !¿ Big Grin Thanks guys. funny you should mention that old oak.... thats exactly what this was. It was a board from the kitchen table in the house I was born in, since derelict and so has senimental attachment too. Can tell you though, it was a bitch to plane. Whatever crud got into it over the years (the open grain is actually black) I wore a set of planer blades to blunt bringing just a few boards back to true. Nice to have it though.
Some details, I'm using a 12" x 6" x 2" heatsink per side and it gets good and hot, at least 50 deg each side I reckon. I can hold my hands for 10 secs ok, but it gets uncomforable after that. My DMM with temp probe is outside in the workshop, will get an accurate measurement tomorrow night. But right now, you need that size of heatsink for sure. I'll be checking bias again tomorrow night to be sure to see how it settles out.
Sonics: well I've only had a short listen, couple of albums, but initially, the sound seems very refined. My initial impression is that it has the best qualities of both my EL84 amp and the mini aleph. Has a really nice airiness to the highs. Seems to be a little lower gain than the mini-aleph too, I seem to have the volume knob up a little more on the pre. Bearing in mind this amp has not been running for more than 2 hours, it sounds very good - well worth the build and I do think it improves on the mini-aleph. Maybe its just the extra power of course (mini was 10wpc) but there is a lovely kind of unforced nature to the sound. Need to try it out on some dynamic speakers too (mine are quad 57s).
Thanks to all.....
Fran
Some details, I'm using a 12" x 6" x 2" heatsink per side and it gets good and hot, at least 50 deg each side I reckon. I can hold my hands for 10 secs ok, but it gets uncomforable after that. My DMM with temp probe is outside in the workshop, will get an accurate measurement tomorrow night. But right now, you need that size of heatsink for sure. I'll be checking bias again tomorrow night to be sure to see how it settles out.
Sonics: well I've only had a short listen, couple of albums, but initially, the sound seems very refined. My initial impression is that it has the best qualities of both my EL84 amp and the mini aleph. Has a really nice airiness to the highs. Seems to be a little lower gain than the mini-aleph too, I seem to have the volume knob up a little more on the pre. Bearing in mind this amp has not been running for more than 2 hours, it sounds very good - well worth the build and I do think it improves on the mini-aleph. Maybe its just the extra power of course (mini was 10wpc) but there is a lovely kind of unforced nature to the sound. Need to try it out on some dynamic speakers too (mine are quad 57s).
Thanks to all.....
Fran
that old oak...
My piece of oak is from my paternal grandmothers table. Hoping to just remove some aging, giving it a rustic look.
I have an old Akai reel2reel tape recorder, bought in 1967 at the Webb TX. AFB px, that has EL84s
used single ended. It has a very fine high end. Only 5 beautiful watts .
So, if the F5 has its qualities at a higher power, I will be in heaven.
I've read somewhere that the F5 will need a pre-amp with extra gain.
Guess I'll use my HarmonKardon 1 for awhile.
woodturner-fran said:
My piece of oak is from my paternal grandmothers table. Hoping to just remove some aging, giving it a rustic look.
I have an old Akai reel2reel tape recorder, bought in 1967 at the Webb TX. AFB px, that has EL84s
used single ended. It has a very fine high end. Only 5 beautiful watts
.So, if the F5 has its qualities at a higher power, I will be in heaven.
I've read somewhere that the F5 will need a pre-amp with extra gain.
Guess I'll use my HarmonKardon 1 for awhile.
A question for those running without current control/ temp compensation....
Have you tracked voltage across R11 and 12 with case temp? I'm finding that voltage can rise by about 0.6-0.7V when my case is closed. Is this ok? R11/12 get to about 60 deg C.
Heatsinks are getting to 45-50 deg C
I have some imbalance between Q3 and 4 on one channel. What I think is wrong is that R11 and 12 on this channel got a roasting so maybe have drifted. If the resistance has drifted that would cause it right? This leads to higher offset naturally, but will it affect the sound?
Thanks,
Fran
EDIT: I'm thinking strongly of reconnecting the thermistors and then also R15 IIRC. Might leave things a little more stable.
Have you tracked voltage across R11 and 12 with case temp? I'm finding that voltage can rise by about 0.6-0.7V when my case is closed. Is this ok? R11/12 get to about 60 deg C.
Heatsinks are getting to 45-50 deg C
I have some imbalance between Q3 and 4 on one channel. What I think is wrong is that R11 and 12 on this channel got a roasting so maybe have drifted. If the resistance has drifted that would cause it right? This leads to higher offset naturally, but will it affect the sound?
Thanks,
Fran
EDIT: I'm thinking strongly of reconnecting the thermistors and then also R15 IIRC. Might leave things a little more stable.